public class Rational {
    int numerator = 1 ;   //分子
    int denominator = 1; //分母
    void setNumerator(int a) {  //设置分子
        int c=f(Math.abs(a),denominator);  //计算最大公约数
        numerator = a/c;
        denominator = denominator/c;
        if(numerator<0&&denominator<0) {
            numerator = -numerator;
            denominator = -denominator;
        }
    }
    void setDenominator(int b) {  //设置分母
        int c=f(numerator,Math.abs(b));  //计算最大公约数
        numerator = numerator/c;
        denominator = b/c;
        if(numerator<0&&denominator<0) {
            numerator = -numerator;
            denominator = -denominator;
        }
    }
    int getNumerator() {
        return numerator;
    }
    int getDenominator() {
        return denominator;
    }
    int f(int a,int b) { //求a和b的最大公约数
        if(a==0) {
            return 1;
        }
        if(a<b) {
            int c=a;
            a=b;
            b=c;
        }
        int r=a%b;
        while(r!=0) {
            a=b;
            b=r;
            r=a%b;
        }
        return b;
    }
    Rational add(Rational r) {  //加法运算
        int a=r.getNumerator();
        int b=r.getDenominator();
        int newNumerator=numerator*b+denominator*a; //计算出新分子
        int newDenominator=denominator*b;           //计算出新分母
        Rational result=new Rational();
        result.setNumerator(newNumerator);
        result.setDenominator(newDenominator);
        return result;
    }
    Rational sub(Rational r) {  //减法运算
        int a=r.getNumerator();
        int b=r.getDenominator();
        int newNumerator=numerator*b-denominator*a;
        int newDenominator=denominator*b;
        Rational result=new Rational();
        result.setNumerator(newNumerator);
        result.setDenominator(newDenominator);
        return result;
    }
    Rational muti(Rational r) { //乘法运算
        int a=r.getNumerator();
        int b=r.getDenominator();
        int newNumerator=numerator*a;
        int newDenominator=denominator*b;
        Rational result=new Rational();
        result.setNumerator(newNumerator);
        result.setDenominator(newDenominator);
        return result;
    }
    Rational div(Rational r)  { //除法运算
        int a=r.getNumerator();
        int b=r.getDenominator();
        int newNumerator=numerator*b;
        int newDenominator=denominator*a;
        Rational result=new Rational();
        if(a==0) {
            System.out.println("该算式无解");
            result.setNumerator(0);
        }
        else {
            result.setNumerator(newNumerator);
            result.setDenominator(newDenominator);
        }
        return result;
    }
}
